1. Field of the Invention
The present invention relates to a thermoplastic elastomer composition. More particularly it relates to a thermoplastic elastomer composition containing a syndiotactic polypropylene having more excellent rubber-like properties and heat resistance up to the high temperature region and useful for various applications where the use thereof at a high temperature region is required, such as hoses of automobiles, construction machinery, etc., sealing materials for automobiles, sheet materials for civil construction, sealing materials, and tire members.
2. Description of the Related Art
A thermoplastic elastomer has been known in the art and can be obtained by mixing an elastomer component with a thermoplastic resin. Further, thermoplastic elastomer composition has been known in the art and can be obtained by vulcanizing (or cross-linking) the elastomer component during the mixing process to dynamically cause vulcanization and secure a greater rubber elasticity. These have been noted as a polymer composition capable of giving the desired properties of the elasticity inherent to rubber and other inherent properties plus the thermoplastic moldability of a thermoplastic resin etc. The thermoplastic elastomer composition, however, is superior in heat resistance when a thermoplastic resin having a high heat deformation temperature is used, but has an excessively high Young's modulus and loses its rubber-like properties or flexibility. When an excessive amount of rubber is used, there was the problem that the processability of the elastomer composition as a thermoplastic material became poor. Conversely, when a resin having a low modulus of elasticity is used, since a resin generally also has a low heat deformation temperature, the rubber elasticity is improved, but the heat resistance (heat deformation resistance) becomes poor.